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şeyda şen Cagatay - One of the best experts on this subject based on the ideXlab platform.

  • investigation of biosorption of gemazol turquise blue g reactive dye by dried rhizopus arrhizus in batch and Continuous Systems
    2006
    Co-Authors: Zumriye Aksu, şeyda şen Cagatay
    Abstract:

    Abstract Gemazol Turquise Blue-G, a vinyl sulfone mono-azo type reactive dye, containing copper-phtlalocyanine as cromofor group, was removed from its aqueous solution in batch and Continuous packed bed sorption Systems by using dried Rhizopus arrhizus as a biosorbent. Operating variables studied were temperature, initial pH, initial dye concentration and sorbent dosage in the batch stirred system and flow rate and inlet dye concentration in the Continuous packed bed. In the batch system, the fungal biomass exhibited the highest dye uptake as 773.0 mg g−1 at 45 °C, at an initial pH value of 2.0, at an initial dye concentration of 812.6 mg l−1 for a biomass dosage of 0.5 g l−1. The Freundlich, Langmuir and Redlich–Peterson adsorption models were used for the mathematical description of the biosorption equilibrium and isotherm constants were evaluated at different temperatures. Equilibrium data fitted well the Langmuir model in the studied concentration (100–800 mg l−1) and temperature (25–45 °C) ranges. Sorption data were fitted to pseudo first-order, pseudo second-order and saturation type kinetic models assuming that the external mas transfer limitations in the system can be neglected. The dye uptake process was found to follow pseudo second-order and saturation type kinetics. The thermodynamic parameters calculated showed that the adsorption process is feasible and has an endothermic character. The effect of operating parameters on the sorption characteristics of R. arrhizus in the Continuous packed bed was investigated at pH 2.0 and at 25 °C. Data confirmed that the total amount of sorbed dye and column sorption capacity decreased with increasing flow rate and increased with increasing inlet dye concentration. The maximum column biosorption capacity of dried R. arrhizus cells was 823.8 mg g−1 at the highest inlet dye concentration of 776.3 mg l−1 at the minimum flow rate of 0.8 ml min−1. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design and to predict the breakthrough curves. The model was found suitable for describing the whole part of dynamic behavior of the column with respect to flow rate and inlet dye concentration.

  • investigation of biosorption of gemazol turquise blue g reactive dye by dried rhizopus arrhizus in batch and Continuous Systems
    2006
    Co-Authors: Zumriye Aksu, şeyda şen Cagatay
    Abstract:

    Abstract Gemazol Turquise Blue-G, a vinyl sulfone mono-azo type reactive dye, containing copper-phtlalocyanine as cromofor group, was removed from its aqueous solution in batch and Continuous packed bed sorption Systems by using dried Rhizopus arrhizus as a biosorbent. Operating variables studied were temperature, initial pH, initial dye concentration and sorbent dosage in the batch stirred system and flow rate and inlet dye concentration in the Continuous packed bed. In the batch system, the fungal biomass exhibited the highest dye uptake as 773.0 mg g−1 at 45 °C, at an initial pH value of 2.0, at an initial dye concentration of 812.6 mg l−1 for a biomass dosage of 0.5 g l−1. The Freundlich, Langmuir and Redlich–Peterson adsorption models were used for the mathematical description of the biosorption equilibrium and isotherm constants were evaluated at different temperatures. Equilibrium data fitted well the Langmuir model in the studied concentration (100–800 mg l−1) and temperature (25–45 °C) ranges. Sorption data were fitted to pseudo first-order, pseudo second-order and saturation type kinetic models assuming that the external mas transfer limitations in the system can be neglected. The dye uptake process was found to follow pseudo second-order and saturation type kinetics. The thermodynamic parameters calculated showed that the adsorption process is feasible and has an endothermic character. The effect of operating parameters on the sorption characteristics of R. arrhizus in the Continuous packed bed was investigated at pH 2.0 and at 25 °C. Data confirmed that the total amount of sorbed dye and column sorption capacity decreased with increasing flow rate and increased with increasing inlet dye concentration. The maximum column biosorption capacity of dried R. arrhizus cells was 823.8 mg g−1 at the highest inlet dye concentration of 776.3 mg l−1 at the minimum flow rate of 0.8 ml min−1. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design and to predict the breakthrough curves. The model was found suitable for describing the whole part of dynamic behavior of the column with respect to flow rate and inlet dye concentration.

Zumriye Aksu - One of the best experts on this subject based on the ideXlab platform.

  • investigation of biosorption of gemazol turquise blue g reactive dye by dried rhizopus arrhizus in batch and Continuous Systems
    2006
    Co-Authors: Zumriye Aksu, şeyda şen Cagatay
    Abstract:

    Abstract Gemazol Turquise Blue-G, a vinyl sulfone mono-azo type reactive dye, containing copper-phtlalocyanine as cromofor group, was removed from its aqueous solution in batch and Continuous packed bed sorption Systems by using dried Rhizopus arrhizus as a biosorbent. Operating variables studied were temperature, initial pH, initial dye concentration and sorbent dosage in the batch stirred system and flow rate and inlet dye concentration in the Continuous packed bed. In the batch system, the fungal biomass exhibited the highest dye uptake as 773.0 mg g−1 at 45 °C, at an initial pH value of 2.0, at an initial dye concentration of 812.6 mg l−1 for a biomass dosage of 0.5 g l−1. The Freundlich, Langmuir and Redlich–Peterson adsorption models were used for the mathematical description of the biosorption equilibrium and isotherm constants were evaluated at different temperatures. Equilibrium data fitted well the Langmuir model in the studied concentration (100–800 mg l−1) and temperature (25–45 °C) ranges. Sorption data were fitted to pseudo first-order, pseudo second-order and saturation type kinetic models assuming that the external mas transfer limitations in the system can be neglected. The dye uptake process was found to follow pseudo second-order and saturation type kinetics. The thermodynamic parameters calculated showed that the adsorption process is feasible and has an endothermic character. The effect of operating parameters on the sorption characteristics of R. arrhizus in the Continuous packed bed was investigated at pH 2.0 and at 25 °C. Data confirmed that the total amount of sorbed dye and column sorption capacity decreased with increasing flow rate and increased with increasing inlet dye concentration. The maximum column biosorption capacity of dried R. arrhizus cells was 823.8 mg g−1 at the highest inlet dye concentration of 776.3 mg l−1 at the minimum flow rate of 0.8 ml min−1. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design and to predict the breakthrough curves. The model was found suitable for describing the whole part of dynamic behavior of the column with respect to flow rate and inlet dye concentration.

  • investigation of biosorption of gemazol turquise blue g reactive dye by dried rhizopus arrhizus in batch and Continuous Systems
    2006
    Co-Authors: Zumriye Aksu, şeyda şen Cagatay
    Abstract:

    Abstract Gemazol Turquise Blue-G, a vinyl sulfone mono-azo type reactive dye, containing copper-phtlalocyanine as cromofor group, was removed from its aqueous solution in batch and Continuous packed bed sorption Systems by using dried Rhizopus arrhizus as a biosorbent. Operating variables studied were temperature, initial pH, initial dye concentration and sorbent dosage in the batch stirred system and flow rate and inlet dye concentration in the Continuous packed bed. In the batch system, the fungal biomass exhibited the highest dye uptake as 773.0 mg g−1 at 45 °C, at an initial pH value of 2.0, at an initial dye concentration of 812.6 mg l−1 for a biomass dosage of 0.5 g l−1. The Freundlich, Langmuir and Redlich–Peterson adsorption models were used for the mathematical description of the biosorption equilibrium and isotherm constants were evaluated at different temperatures. Equilibrium data fitted well the Langmuir model in the studied concentration (100–800 mg l−1) and temperature (25–45 °C) ranges. Sorption data were fitted to pseudo first-order, pseudo second-order and saturation type kinetic models assuming that the external mas transfer limitations in the system can be neglected. The dye uptake process was found to follow pseudo second-order and saturation type kinetics. The thermodynamic parameters calculated showed that the adsorption process is feasible and has an endothermic character. The effect of operating parameters on the sorption characteristics of R. arrhizus in the Continuous packed bed was investigated at pH 2.0 and at 25 °C. Data confirmed that the total amount of sorbed dye and column sorption capacity decreased with increasing flow rate and increased with increasing inlet dye concentration. The maximum column biosorption capacity of dried R. arrhizus cells was 823.8 mg g−1 at the highest inlet dye concentration of 776.3 mg l−1 at the minimum flow rate of 0.8 ml min−1. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design and to predict the breakthrough curves. The model was found suitable for describing the whole part of dynamic behavior of the column with respect to flow rate and inlet dye concentration.

James Lam - One of the best experts on this subject based on the ideXlab platform.

  • a delay partitioning projection approach to stability analysis of Continuous Systems with multiple delay components
    2009
    Co-Authors: James Lam, Zhan Shu, Zidong Wang
    Abstract:

    An effective approach is introduced to study the stability of Continuous Systems with multiple timevarying delay components. By employing a new Lyapunov?Krasovskii functional form based on delay partitioning, delay-dependent stability criteria are established for cases with or without the information of the delay rates. The contribution of the paper is 2-fold. First, it provides an improvement, as well as generalisation, of the existing stability criteria for Continuous Systems with multiple time-varying delay components. Second, it is illustrated numerically that the approach can be applied to estimate the delay bound for system stability in the single delay case with reduction both in conservatism and computational complexity when compared with the existing methods.

  • stability analysis for Continuous Systems with two additive time varying delay components
    2007
    Co-Authors: James Lam, Huijun Gao, Changhong Wang
    Abstract:

    This paper presents a new result of stability analysis for Continuous Systems with two additive time-varying delay components, which represent a general class of delay Systems with strong application background in network based control Systems. This criterion is expressed as a set of linear matrix inequalities, which can be readily tested by using standard numerical software. A numerical example is provided to show the effectiveness and advantage of the proposed stability condition.

Z K Liu - One of the best experts on this subject based on the ideXlab platform.

Zidong Wang - One of the best experts on this subject based on the ideXlab platform.

  • a delay partitioning projection approach to stability analysis of Continuous Systems with multiple delay components
    2009
    Co-Authors: James Lam, Zhan Shu, Zidong Wang
    Abstract:

    An effective approach is introduced to study the stability of Continuous Systems with multiple timevarying delay components. By employing a new Lyapunov?Krasovskii functional form based on delay partitioning, delay-dependent stability criteria are established for cases with or without the information of the delay rates. The contribution of the paper is 2-fold. First, it provides an improvement, as well as generalisation, of the existing stability criteria for Continuous Systems with multiple time-varying delay components. Second, it is illustrated numerically that the approach can be applied to estimate the delay bound for system stability in the single delay case with reduction both in conservatism and computational complexity when compared with the existing methods.